Beginner breadboarded fuzz issue

[Locrian99]

Here are the voltages
First is q1 c-b-e then q2 c-b-e
1.38
.57
0

4.69
1.38
.76

[GibsonGM]

You got some weird voltages there, but hang on, I think maybe someone INTIMATELY familiar with yer fuzz might happen along soon!

[Locrian99]

Yes they are weird when I look at what the electro smash page says on voltage.   I'm going to play around with r4's value as the collector and emitter voltage from q2 are pretty close to recommended 4.5, and .5 recommended but too much of that .5 is making it back around to the base and I'm already running 150k there.   I'll just keep going until that gets to .2 as well as I guess keep upping the 33k feeding the collector of q1.   But those values will be no where near regular by the time I get there.   Seems like I have to be doing something wrong here lol

[GibsonGM]

Hang in there bud...help WILL be coming, LOL....just takes some time for your problem to be seen...

[Locrian99]

Well I figured it out and I'm a little embarrassed to  :icon_confused:say what it was.   I always work on my pedals after the kiddos go to bed.   Amp is on 2.   It's fine for everything I do, and typically I can turn the volume knob down some no issue.   Well amp at 3 I can turn down all the way it sounds fine and cleans up nicely.   I feel a little silly now.   Still doesn't explain the weird voltages.    I tried a 470k in place of the 100k and it didn't really effect base voltage at c1 at all. 

[duck_arse]

Yes they are weird when I look at what the electro smash page says on voltage.   I'm going to play around with r4's value as the collector and emitter voltage from q2 are pretty close to recommended 4.5, and .5 recommended but too much of that .5 is making it back around to the base and I'm already running 150k there.   I'll just keep going until that gets to .2 as well as I guess keep upping the 33k feeding the collector of q1.   But those values will be no where near regular by the time I get there.   Seems like I have to be doing something wrong here lol

if your Q1 has emitter at ground, a silicon transistor base can't be anything but 650mV, plus/minus a few. you'll never get it to 200mV, unless you switch to germanium. I think yer volys measured is good for Si, try messing w/ bias on Q2, see if you find a bias point you like, and leave it there. don't worry about the voltages [after you've measured and recorded them] .

[antonis]

What duck_arse said..

Q1 Collector voltage calls for about 230μA quiescent current, which in turn calls for about 1.9μA Base current (h_FE = 120)..
That current creates a voltage drop of 190mV across R1 (100k) which is accordance with Q2 Emitter voltage minus Q1 Base voltage..
(actually, h_FE of 120 comes as an estimation after your measurements.. )

What puzzles me is Q2 Collector voltage 'cause for a 760μA Emitter current (.76/1k), Collector should sit at about 2.5V [9 - (0.00076 X 8530)]..

Are you sure for R4 "correct" value..??

[Locrian99]

I'm running a 5.6k resistor at r4 to get it to the 4.69.

[antonis]

If so, ALL your voltage measurements are FINE..!!

So, to recap.. What's your issue..??

[Locrian99]

At this point there isn't one anymore.  The volume thing was my issue, which was operator error in the end.  I just got done doing some more tinkering on it decided I liked a 2n4123 better in q1.  Had to change r4 to a 3k and 680 in series surprisingly to me I could tell the difference between the 3.9k sitting at 4.45v and the two in series sitting at 4.63v with my ears.   I was surprised I hadn't change r4 with the change to q1.  Went with 150k for r1 sounded better. And put a 680pf cap between the base and collector of q2.   Sounds good to my ears at this point.   Thank you guys for all your help and ideas here.   I'd say this is ready to move from the breadboard to vero which I'll start hopefully tonight.

[Locrian99]

Ended up finding a vero layout with a bmp tone stack with the millers caps so Added that to the breadboard to try it and liked it so put it all on vero and works great for it boxed up.   First not kit and first vero pedal for me.   Butchered the paint job on the enclosure I was going for, it looks like my first attempt at it lol.  Anyways thanks for the help guys.  Is there a way to mark the thread closed or solved.   

[GibsonGM]

Good work, Locrian.    You don't have to mark the thread any way - it will disappear as new topics are added.  There are even topics on paint, BTW, lol.

[antonis]

Is there a way to mark the thread closed or solved.

The easiest way is by begging on your knees (equipped with some bottles of fine cider, also) duck-arse to settle your wish..

[duck_arse]

glub glub glub, yeah, ok, it's glub glub closed.

[GibsonGM]

Are you SURE?

[Phend]

Cool, everything I build sounds good to my ears too.
And that is what diy is all about..the final test, the ole vestibulocochlear nerves. (old in my case)
Hunh

[iainpunk]

Is there a way to mark the thread closed or solved.

The easiest way is by begging on your knees (equipped with some bottles of fine cider, also) duck-arse to settle your wish..

still think there should be labels or flairs a moderator can add to a thread to mark it as [solved] [de-railed] or a few difficulty categories to denote the level of the circuit(s) in question

cheers

[antonis]

still think there should be labels or flairs a moderator can add to a thread to mark it as [solved] [de-railed] or a few difficulty categories to denote the level of the circuit(s) in question

As usual, you DO insist for half-arsed works, like almost all of yours, Iain..
(I tend to presume that's a bombed city residents feature..)

[duck_arse]

I lived thru the 70's once - I don't want to be wearing flairs again.

and how do we know a derail when we see it - when most of the time, we cause it?

[Phend]

Texting while driving is hazardous.
You might get derailed.